In recent years, toners for electrophotography fixable at a low temperature have been desired from the viewpoint of the demands of energy conservation and high-speed printing in an electrophotographic apparatus. On the other hand, toners are likely to have smaller particle sizes from the viewpoint of achieving even higher image qualities.
Processes for preparing toners include a melt-kneading and pulverization method, and a wet process such as an emulsification and aggregation method. When a toner containing a resin binder containing a crystalline polyester as a main component is prepared by the melt-kneading and pulverization method, it is difficult to control the pulverization, thereby making it impractical. On the other hand, JP-2003-167380 A and JP-2001-305796 A each discloses an invention relating to the preparation of a toner by an emulsification and aggregation method, which is a wet process. However, a resin that can be applied in this method is limited, and a strong mechanical force is required during emulsification. In addition, JP-A-Hei-10-319639 discloses a method including the step of emulsifying the components containing a hydrophobic organic solvent as an essential component, while phase-converting the components to an aqueous phase with high shearing. However, the low-temperature fixing cannot be realized by the polyester used in this method. Further, JP-2004-51806 A discloses a process for preparing a resin dispersion, but the dispersed particles contained therein have a large particle size, thereby making unsatisfactory to be used for a toner for high-image quality.